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NCT Number: NCT07643376

Evaluation of Metabolic Parameters, Intestinal Permeability and Gastrointestinal Symptoms After Bariatric Surgery in Body Weight Management

This study aims to evaluate the changes in metabolic parameters, intestinal permeability, and gastrointestinal symptoms in individuals who have undergone bariatric surgery (Laparoscopic Sleeve Gastrectomy - LSG) for obesity treatment.

Obesity is a chronic disease associated with serious health complications including type 2 diabetes, hypertension, cardiovascular disease, and metabolic disorders. Bariatric surgery is currently the most effective treatment method for morbid obesity. However, monitoring patients after surgery in terms of metabolic health, gut permeability, and gastrointestinal symptoms is crucial for long-term success.

In this study, 40 volunteers (aged 19-50) who have undergone LSG surgery within the last month will be followed for 6 months. At the beginning of the study and 6 months later, the following will be assessed:

* Metabolic parameters: fasting blood glucose, total cholesterol, triglycerides, high-density lipoprotein (HDL), low-density lipoprotein (LDL), very low-density lipoprotein (VLDL) cholesterol, and insulin levels * Intestinal permeability markers: zonulin, secretory immunoglobulin A (IgA), and lipopolysaccharide (LPS) levels * Gastrointestinal symptoms: assessed using the Gastrointestinal Symptom Rating Scale (GSRS) * Anthropometric measurements: body weight, height, waist and hip circumference, BMI * Nutritional intake: 3-day dietary records

The study will be conducted at Bursa Yıldırım Doruk Hospital, General Surgery Clinic. Results will contribute to understanding the relationship between bariatric surgery and gut health, potentially helping to prevent postoperative complications.

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Key information

Conditions

Obesity, Morbid Bariatric Surgery Body Weight Gastrointestinal Symptoms Glucose Metabolism Disorders Hyperinsulinism Insulin Resistance Intestinal Permeability Metabolic Diseases Metabolic Syndrome Nutrition Disorders Nutritional and Metabolic Diseases Obesity Overnutrition Overweight Pathological Conditions, Signs and Symptoms Signs and Symptoms

Age range

19 year–50 year

Sex eligibility

All sexes

Study type

Observational

Primary location

Bursa Yıldırım Doruk Hospital

Bursa, 16310, Turkey (Türkiye)

Location contact

Betül GÜLŞEN, Assoc. Prof.

CONTACT

[email protected]

+903246253300

Betül GÜLŞEN, Assoc. Prof.

PRINCIPAL_INVESTIGATOR

Doğukan DURAK;, Assoc. Prof.

CONTACT

[email protected]

+905327243733

Doğukan Durak, Assoc. Prof.

SUB_INVESTIGATOR

Seher ŞEN, Asst. Prof.

SUB_INVESTIGATOR

Tuğçe Nur Doganay Yıldırım, MSc, RD

SUB_INVESTIGATOR

Özlem ÖZPAK AKKUŞ, Assoc. Prof.

PRINCIPAL_INVESTIGATOR

About this study

Obesity is defined by the World Health Organization (WHO) as abnormal or excessive fat accumulation that presents a risk to health. Bariatric surgery, particularly Laparoscopic Sleeve Gastrectomy (LSG), is considered the most effective long-term treatment for morbid obesity.

This prospective observational study will be conducted at Bursa Yıldırım Doruk Hospital with 40 volunteers who have undergone LSG within the last month. Participants will be evaluated at baseline (immediately after surgery) and at 6 months post-surgery.

Assessments include:

  • Anthropometric Measurements: Body weight, height, waist and hip circumference will be measured. BMI and waist-to-hip ratio will be calculated according to WHO criteria.
  • Biochemical Parameters: Fasting blood glucose, total cholesterol, triglycerides, high-density lipoprotein (HDL), low-density lipoprotein (LDL), very low-density lipoprotein (VLDL) cholesterol, and insulin levels will be obtained from patient records. Zonulin, secretory immunoglobulin A (IgA), and lipopolysaccharide (LPS) levels will be analyzed using ELISA method (Biotek TS800) with commercial kits (RelAssay® Diagnostics, Ankara, Turkey) at Ankara Diagen Laboratory. Samples will be stored at -20°C until analysis.
  • Gastrointestinal Symptom Rating Scale (GSRS): A validated 15-item scale assessing five dimensions: diarrhea, indigestion, constipation, abdominal pain, and reflux. Scores range from 1 (no discomfort) to 7 (very severe discomfort). Turkish validity and reliability was established by Turan and Asti (2011).
  • Dietary Assessment: 3-day dietary records will be collected and analyzed using the Nutrition Information System (BeBIS) 8.2 software. Results will be evaluated according to the Turkish Dietary Guidelines 2022 (TUBER 2022).

Statistical analyses will be performed using the Statistical Package for the Social Sciences (SPSS) 22.0. Normal distribution will be assessed using Kolmogorov-Smirnov/Shapiro-Wilk tests. Results will be expressed as mean ± standard deviation for continuous variables and frequency/percentage for categorical variables.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Underwent Laparoscopic Sleeve Gastrectomy (LSG) within the last 1 month
  • Aged between 19-50 years
  • BMI ≥40 kg/m² or BMI ≥35 kg/m² with obesity-related comorbidities
  • Signed informed consent form
  • Non-smoker and non-alcohol dependent

Exclusion criteria

  • Did not undergo or is not planned to undergo LSG
  • Outside the age range of 19-50 years
  • Did not sign the informed consent form
  • BMI <40 kg/m² or BMI <35 kg/m² without obesity-related comorbidities
  • Smoker or alcohol dependent
  • Has an inflammatory disease
  • Currently using probiotics, antibiotics, or fiber supplements
  • Has a psychiatric disorder

Treatment and study plan

Clinical and biochemical assessment

Other

Participants will undergo two assessment visits: at baseline (within 1 month post-surgery) and at 6-month follow-up. Each visit includes anthropometric measurements (body weight, height, waist and hip circumference, BMI), biochemical blood analysis (fasting glucose, lipid profile, insulin, zonulin, secretory IgA, LPS), gastrointestinal symptom evaluation via GSRS, and 3-day dietary records.

Other names: Anthropometric Measurement, Biochemical Blood Analysis, Gastrointestinal Symptom Rating Scale (GSRS), 3-Day Dietary Record, Intestinal Permeability Assessment

Primary outcomes

  1. Change in Fasting Blood Glucose Concentration (mg/dL)

    Time frame: Baseline and 6 months

    Change in serum fasting blood glucose levels after 12-hour fasting between baseline and 6-month follow-up.

  2. Change in Total Cholesterol Concentration (mg/dL)

    Time frame: Baseline and 6 months

    Change in serum total cholesterol levels after 12-hour fasting between baseline and 6-month follow-up.

  3. Change in Triglyceride Concentration (mg/dL)

    Time frame: Baseline and 6 months

    Change in serum triglyceride levels after 12-hour fasting between baseline and 6-month follow-up.

  4. Change in HDL Cholesterol Concentration (mg/dL)

    Time frame: Baseline and 6 months

    Change in serum high-density lipoprotein (HDL) cholesterol levels after 12-hour fasting between baseline and 6-month follow-up.

  5. Change in LDL Cholesterol Concentration (mg/dL)

    Time frame: Baseline and 6 months

    Change in serum low-density lipoprotein (LDL) cholesterol levels after 12-hour fasting between baseline and 6-month follow-up.

  6. Change in VLDL Cholesterol Concentration (mg/dL)

    Time frame: Baseline and 6 months

    Change in serum very low-density lipoprotein (VLDL) cholesterol levels after 12-hour fasting between baseline and 6-month follow-up.

  7. Change in Fasting Insulin Concentration (µIU/mL)

    Time frame: Baseline and 6 months

    Change in serum fasting insulin levels after 12-hour fasting between baseline and 6-month follow-up.

  8. Change in Serum Zonulin Concentration (ng/mL)

    Time frame: Baseline and 6 months

    Change in serum zonulin levels assessed by ELISA method between baseline and 6-month follow-up.

  9. Change in Serum Secretory IgA Concentration (mg/dL)

    Time frame: Baseline and 6 months

    Change in serum secretory IgA levels assessed by ELISA method between baseline and 6-month follow-up.

  10. Change in Serum LPS Concentration (EU/mL)

    Time frame: Baseline and 6 months

    Change in serum lipopolysaccharide (LPS) levels assessed by ELISA method between baseline and 6-month follow-up.

  11. Change in Gastrointestinal Symptom Rating Scale (GSRS) Total Score (1-7)

    Time frame: Baseline and 6 months

    Change in total score of the Gastrointestinal Symptom Rating Scale (GSRS) between baseline and 6-month follow-up. The scale consists of 15 items across 5 subscales; scores range from 1 to 7, with higher scores indicating more severe gastrointestinal symptoms.

Secondary outcomes

  1. Change in Body Weight (kg)

    Time frame: Baseline and 6 months

    Change in body weight between baseline and 6-month follow-up.

  2. Change in Body Mass Index (kg/m²)

    Time frame: Baseline and 6 months

    Change in BMI between baseline and 6-month follow-up. Weight and height will be combined to report BMI in kg/m².

  3. Change in Waist Circumference (cm)

    Time frame: Baseline and 6 months

    Change in waist circumference between baseline and 6-month follow-up.

  4. Change in Hip Circumference (cm)

    Time frame: Baseline and 6 months

    Change in hip circumference between baseline and 6-month follow-up.

  5. Change in Waist-to-Hip Ratio

    Time frame: Baseline and 6 months

    Change in waist-to-hip ratio between baseline and 6-month follow-up. Waist and hip circumference measurements will be combined to calculate the waist-to-hip ratio.

  6. Change in Daily Energy Intake (kcal/day)

    Time frame: Baseline and 6 months

    Change in daily energy intake assessed by 3-day dietary intake records between baseline and 6-month follow-up. Data will be analyzed using BeBIS 8.2 software.

  7. Change in Daily Protein Intake (g/day)

    Time frame: Baseline and 6 months

    Change in daily protein intake assessed by 3-day dietary intake records between baseline and 6-month follow-up. Data will be analyzed using BeBIS 8.2 software.

  8. Change in Daily Carbohydrate Intake (g/day)

    Time frame: Baseline and 6 months

    Change in daily carbohydrate intake assessed by 3-day dietary intake records between baseline and 6-month follow-up. Data will be analyzed using BeBIS 8.2 software.

  9. Change in Daily Fat Intake (g/day)

    Time frame: Baseline and 6 months

    Change in daily fat intake assessed by 3-day dietary intake records between baseline and 6-month follow-up. Data will be analyzed using BeBIS 8.2 software.

Study contacts

Contact information is provided by the study sponsor or research team.

Betül GÜLŞEN, Assoc. Prof.

CONTACT

[email protected]

+903246253300

Özlem ÖZPAK AKKUŞ, Assoc. Prof.

CONTACT

[email protected]

+903246253300

Sponsors and collaborators

Lead sponsor

Toros University

Other

Registry information

Official study title

Evaluation of Postoperative Metabolic Parameters, Intestinal Permeability and Gastrointestinal Symptoms in Body Weight Management After Laparoscopic Sleeve Gastrectomy

Acronym: METABAR

Important dates

Study start
2026
Primary completion
2027
Study completion
2027
First posted
Jun 11, 2026
Registry last updated
Jun 11, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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